lib/tdb2/traverse.c

   1  /*
   2    Trivial Database 2: traverse function.
   3    Copyright (C) Rusty Russell 2010
   4
   5    This library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 3 of the License, or (at your option) any later version.
   9
  10    This library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17 */
  18 #include "private.h"
  19 #include <ccan/likely/likely.h>
  20
  21 int64_t tdb_traverse_(struct tdb_context *tdb,
  22                       int (*fn)(struct tdb_context *,
  23                                 TDB_DATA, TDB_DATA, void *),
  24                       void *p)
  25 {
  26         enum TDB_ERROR ecode;
  27         struct traverse_info tinfo;
  28         struct tdb_data k, d;
  29         int64_t count = 0;
  30
  31         if (tdb->flags & TDB_VERSION1) {
  32                 count = tdb1_traverse(tdb, fn, p);
  33                 if (count == -1)
  34                         return TDB_ERR_TO_OFF(tdb->last_error);
  35                 return count;
  36         }
  37
  38         k.dptr = NULL;
  39         for (ecode = first_in_hash(tdb, &tinfo, &k, &d.dsize);
  40              ecode == TDB_SUCCESS;
  41              ecode = next_in_hash(tdb, &tinfo, &k, &d.dsize)) {
  42                 d.dptr = k.dptr + k.dsize;
  43
  44                 count++;
  45                 if (fn && fn(tdb, k, d, p)) {
  46                         free(k.dptr);
  47                         tdb->last_error = TDB_SUCCESS;
  48                         return count;
  49                 }
  50                 free(k.dptr);
  51         }
  52
  53         if (ecode != TDB_ERR_NOEXIST) {
  54                 return TDB_ERR_TO_OFF(tdb->last_error = ecode);
  55         }
  56         tdb->last_error = TDB_SUCCESS;
  57         return count;
  58 }
  59
  60 enum TDB_ERROR tdb_firstkey(struct tdb_context *tdb, struct tdb_data *key)
  61 {
  62         struct traverse_info tinfo;
  63
  64         if (tdb->flags & TDB_VERSION1) {
  65                 tdb->last_error = TDB_SUCCESS;
  66                 *key = tdb1_firstkey(tdb);
  67                 /* TDB1 didn't set error for last key. */
  68                 if (!key->dptr && tdb->last_error == TDB_SUCCESS) {
  69                         tdb->last_error = TDB_ERR_NOEXIST;
  70                 }
  71                 return tdb->last_error;
  72         }
  73
  74         return tdb->last_error = first_in_hash(tdb, &tinfo, key, NULL);
  75 }
  76
  77 /* We lock twice, not very efficient.  We could keep last key & tinfo cached. */
  78 enum TDB_ERROR tdb_nextkey(struct tdb_context *tdb, struct tdb_data *key)
  79 {
  80         struct traverse_info tinfo;
  81         struct hash_info h;
  82         struct tdb_used_record rec;
  83
  84         if (tdb->flags & TDB_VERSION1) {
  85                 struct tdb_data last_key = *key;
  86                 tdb->last_error = TDB_SUCCESS;
  87                 *key = tdb1_nextkey(tdb, last_key);
  88                 free(last_key.dptr);
  89                 /* TDB1 didn't set error for last key. */
  90                 if (!key->dptr && tdb->last_error == TDB_SUCCESS) {
  91                         tdb->last_error = TDB_ERR_NOEXIST;
  92                 }
  93                 return tdb->last_error;
  94         }
  95
  96         tinfo.prev = find_and_lock(tdb, *key, F_RDLCK, &h, &rec, &tinfo);
  97         free(key->dptr);
  98         if (TDB_OFF_IS_ERR(tinfo.prev)) {
  99                 return tdb->last_error = TDB_OFF_TO_ERR(tinfo.prev);
 100         }
 101         tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
 102
 103         return tdb->last_error = next_in_hash(tdb, &tinfo, key, NULL);
 104 }
 105
 106 static int wipe_one(struct tdb_context *tdb,
 107                     TDB_DATA key, TDB_DATA data, enum TDB_ERROR *ecode)
 108 {
 109         *ecode = tdb_delete(tdb, key);
 110         return (*ecode != TDB_SUCCESS);
 111 }
 112
 113 enum TDB_ERROR tdb_wipe_all(struct tdb_context *tdb)
 114 {
 115         enum TDB_ERROR ecode;
 116         int64_t count;
 117
 118         if (tdb->flags & TDB_VERSION1) {
 119                 if (tdb1_wipe_all(tdb) == -1)
 120                         return tdb->last_error;
 121                 return TDB_SUCCESS;
 122         }
 123
 124         ecode = tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false);
 125         if (ecode != TDB_SUCCESS)
 126                 return tdb->last_error = ecode;
 127
 128         /* FIXME: Be smarter. */
 129         count = tdb_traverse(tdb, wipe_one, &ecode);
 130         if (count < 0)
 131                 ecode = TDB_OFF_TO_ERR(count);
 132         tdb_allrecord_unlock(tdb, F_WRLCK);
 133         return tdb->last_error = ecode;
 134 }